In 1999 the Centers for Disease Control and Prevention issued a report on what might happen if a pandemic virus – similar to the relatively mild virus of 1968 – struck the United States. It estimated that between 89,000 and 207,000 people in the U.S. would die. Why so many?

“The reason for this high toll is the same reason that the CDC has concluded that, despite medical advances, more Americans are now dying from ordinary, endemic influenza than in the past: in 1918, 1957, and even 1968 relatively few people alive had impaired immune systems. Today a large and growing number of people do – primarily the elderly, but also cancer survivors who have undergone chemotherapy or radiation, transplant recipients, those infected with HIV, and others.”

The CDC’s projected figures are much lower than those in a United States Army War College Program Research Paper “The 1918 Flu Pandemic: Implications for Homeland Security in the New Millennium,” which you can find easily by pasting the phrase in quotations into the Google search bar (though I can’t seem to link to it). That paper puts the estimated death toll for a flu pandemic at 1.7 million Americans.